Central Library Delft University

architect: Mecanoo Architects
year: 1992-1998
location: Delft, NL

The most succinct description of this library building would be: a landscape raised up above a mass of technical books (about a million) with a transparent zone with a central hall, reading rooms, study rooms and offices in-between the two, the whole skewered by a cone (housing some more study rooms). It is not often that one can describe a building in such crisp terms. This can only be achieved with an all-in design that is build up of only a few architectural elements in which form, function and technique are inextricably interwoven. This design is a successful instance of such integration: each element integrates architectural, technical, and ecological design objectives into one whole.

The most striking feature is the enormous grass roof. This roof has its ecological advantages, its heat-accumulating and insulating properties, so that the space beneath it is less susceptible to rapid changes in temperature, are useful in any building but certainly in a library. But there is also an architectural reason. The library is located behind the general assembly hall of the university. It would be difficult for a new building to compete with this striking, eloquently canting concrete sculpture. The new library avoids this conflict by not being a building at all but a raked landscape. The formerly paved ground level round the assembly hall is transmuted into a green landscape that rises up gently at the rear to continue as the library's triangular grass roof.

The library is a very compact building, which makes ecological sense, but in combination with the closed grass roof it also raises a problem. The architects wanted a transparent and open interior with lots of natural lighting. In order to achieve this, the facades - in fact the slit left open between the raised landscape and the ground - had to be fully glazed. A climate facade made this possible. And again this also served an architectural objective, the contrast between the 'green' roof on one side of the building and the glass facades on the other reflects the 'technology-landscape of the interior.

The building also makes use of other ecological techniques. As with so many buildings cooling in summer was a bigger problem than heating in winter. To prevent disfiguring the grass roof with cooling units, it was decided to adopt cold storage, a technique that is energy saving into the bargain. Cold is stored in winter in a deep layer of ground water and pumped up in summer.

The green technology in this building may not be very innovative, but the fact that it is so smartly used and so fully integrated in the architectural concept, make the building stand out. It is green architecture without rhetoric.